This invention relates to a drive unit for attachment to a golf trolley whereby the user may achieve powered drive of the trolley, by suitable operation of controls.
Powered drive units for attachment to golf trolleys (so as to motorise an industry-standard push-pull golf trolley) are known. One unit comprises a battery power source to an internal geared drive but was subject to reliability problems with the gear wheels, as well as emitting an unacceptable level of noise.
A basic object of the present invention is the provision of an improved power drive unit for attachment to a golf trolley.
According to the invention there is provided a power drive unit for attachment to a golf trolley comprising:
(i) a drum rotatable about a generally horizontal axis with the external periphery of the drum adapted to seat on the ground and to make frictional contact with the ground for drive purposes,
(ii) a battery within the drum,
(iii) an electric drive motor powerable from the battery,
(iv) a transmission from the drive motor to the drum,
(v) manually operable control means for controlling forward rotation of the drum,
(vi) an end cap at each end of the drum, and
(vii) a final output gear mechanically connected to one end cap via a vibration isolating connection.
The purpose of isolating the final output gear from the end cap is to maintain alignment of this gear when the end cap (and drum to which it is affixed) flexes whilst negotiating rough terrain as frequently occurs when the drive unit negotiates a golf course. This maintains the centre distance between other gears making up speed reduction drive train from the electric motor and prevents the noise caused by this parameter changing during each revolution. In addition any vibration present on the output gear is not transmitted to the end cap which adds to the quietness of operation.
A certain amount of mechanical shock isolation from the outside world to the drive train is also created by this system.
An air gap is provided between the final output gear and the mechanically connected end cap, which air gap minimises any noise transmission from the interior of the drum to the outside.
A yoke bridges co-axial stub shafts co-axial by which yoke the unit is attachable to a golf trolley.
The yoke comprises a top plate, and a pair of side arms.
The top plate incorporates a centering block and a clamp.
The battery is a lead/acid battery.
The battery is carried within the drum by a chassis and secured therein by at least one battery strap.
The chassis is carried by the stub shafts, which project from end walls of the chassis and passing one through each end cap of the drum to be attached to a terminal end of one of each side arms of the yoke.
The chassis also carries the electric motor, a speed controller, and a relay.
The electric motor has an output shaft carrying a pulley to a belt of a first stage of the transmission, the belt driving an idler gear rotatably mounted on a pin carried by one side wall of the chassis, the idler gear having a spur gear in mesh with the output gear, to form a second stage of the transmission.
The gears of acetal copolymer.
The mechanical connection of the end cap to the final output gear is by drive pegs of one member engaging recesses of the other.
The isolating connection comprises a ring or sleeve of resilient material, mounted on each peg and engageable with at least a portion of the associated recesses.
The resilient ring or sleeve is of neoprene, rubber.
The manually operable control means also controls reverse rotation of the drum.